US20070042856A1 - Continuously variable ratio transmission system - Google Patents

Continuously variable ratio transmission system Download PDF

Info

Publication number
US20070042856A1
US20070042856A1 US10/561,727 US56172704A US2007042856A1 US 20070042856 A1 US20070042856 A1 US 20070042856A1 US 56172704 A US56172704 A US 56172704A US 2007042856 A1 US2007042856 A1 US 2007042856A1
Authority
US
United States
Prior art keywords
output
gear train
output shaft
epicyclic gear
variator
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
US10/561,727
Other versions
US7530916B2 (en
Inventor
Christopher Greenwood
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Allison Transmission Inc
Original Assignee
Torotrak Development Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Torotrak Development Ltd filed Critical Torotrak Development Ltd
Assigned to TOROTRAK (DEVELOPMENT) LIMITED reassignment TOROTRAK (DEVELOPMENT) LIMITED ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: GREENWOOD, CHRISTOPHER JOHN
Publication of US20070042856A1 publication Critical patent/US20070042856A1/en
Application granted granted Critical
Publication of US7530916B2 publication Critical patent/US7530916B2/en
Assigned to ALLISON TRANSMISSION, INC. reassignment ALLISON TRANSMISSION, INC. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: TOROTRAK (DEVELOPMENT) LIMITED
Assigned to ALLISON TRANSMISSION, INC. reassignment ALLISON TRANSMISSION, INC. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: TOROTRAK (DEVELOPMENT) LIMITED
Active legal-status Critical Current
Adjusted expiration legal-status Critical

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H37/00—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00
    • F16H37/02—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings
    • F16H37/06—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings with a plurality of driving or driven shafts; with arrangements for dividing torque between two or more intermediate shafts
    • F16H37/08—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings with a plurality of driving or driven shafts; with arrangements for dividing torque between two or more intermediate shafts with differential gearing
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H37/00—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00
    • F16H37/02—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings
    • F16H37/06—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings with a plurality of driving or driven shafts; with arrangements for dividing torque between two or more intermediate shafts
    • F16H37/08—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings with a plurality of driving or driven shafts; with arrangements for dividing torque between two or more intermediate shafts with differential gearing
    • F16H37/0833—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings with a plurality of driving or driven shafts; with arrangements for dividing torque between two or more intermediate shafts with differential gearing with arrangements for dividing torque between two or more intermediate shafts, i.e. with two or more internal power paths
    • F16H37/084—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings with a plurality of driving or driven shafts; with arrangements for dividing torque between two or more intermediate shafts with differential gearing with arrangements for dividing torque between two or more intermediate shafts, i.e. with two or more internal power paths at least one power path being a continuously variable transmission, i.e. CVT
    • F16H37/086—CVT using two coaxial friction members cooperating with at least one intermediate friction member
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H37/00—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00
    • F16H37/02—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings
    • F16H37/06—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings with a plurality of driving or driven shafts; with arrangements for dividing torque between two or more intermediate shafts
    • F16H37/08—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings with a plurality of driving or driven shafts; with arrangements for dividing torque between two or more intermediate shafts with differential gearing
    • F16H37/0833—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings with a plurality of driving or driven shafts; with arrangements for dividing torque between two or more intermediate shafts with differential gearing with arrangements for dividing torque between two or more intermediate shafts, i.e. with two or more internal power paths
    • F16H37/084—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings with a plurality of driving or driven shafts; with arrangements for dividing torque between two or more intermediate shafts with differential gearing with arrangements for dividing torque between two or more intermediate shafts, i.e. with two or more internal power paths at least one power path being a continuously variable transmission, i.e. CVT
    • F16H2037/088—Power split variators with summing differentials, with the input of the CVT connected or connectable to the input shaft
    • F16H2037/0886—Power split variators with summing differentials, with the input of the CVT connected or connectable to the input shaft with switching means, e.g. to change ranges

Definitions

  • the present invention relates to continuously variable ratio transmission systems.
  • a continuously variable ratio transmission system having system input and output shafts and a continuously variable ratio transmission unit (known as a variator) connected to the system input shaft and having a variator output shaft.
  • a mixing epicyclic gear train receives drive from the system input and from the variator input.
  • clutches or other braking elements By appropriate use of clutches or other braking elements, the system can operate in a high-gearing regime or a low-gearing regime. Examples of such transmissions, which disclose arrangements having coaxial system input and output shafts, can be found in JP-A-6-174033 and JP-A-62-255655.
  • Our co-pending United Kingdom patent application 0212186.1 addresses this problem by providing a mixing epicyclic gear train having an input sun gear drivably connected to the variator output shaft, a planet carrier drivably connected to the system input shaft and a first planet gear mounted on the planet carrier and drivingly engaged with the input sun gear.
  • the first planet gear drives a first intermediate output shaft arranged coaxially with the system input shaft and is selectively connectable to the system output shaft via a first clutch.
  • the first planet gear provides the input for a second epicyclic gear train having an output which is selectively connectable to the system output shaft via a braking element.
  • the variator is the lowest efficiency component of the transmission but it enables engine optimisation by ratio matching, resulting in improved overall economy. However, this is not possible at maximum power since this occurs only at one engine speed. If power loss is important, it may be beneficial to sacrifice variable ratio for best efficiency by removing the influence of the variator and operating it at a fixed ratio.
  • the overall result is to potentially avoid a slight reduction in the top speed of the vehicle to which the transmission is fitted.
  • a multi-regime, continuously variable ratio transmission system comprising:
  • variable connected to the system input shaft and having a variator output shaft;
  • a mixing epicyclic gear train having inputs drivably connected to the variator output shaft and the system input shaft and having an output which is selectively connectable to the system output shaft via a first braking element;
  • a second braking element adapted to lock the output of the mixing epicyclic gear train in a stationary position.
  • system input shaft, the system output shaft and the variator are arranged coaxially with each other and with a second epicyclic gear train comprising a second input sun gear driven by the output of the mixing epicyclic gear train and wherein the second braking element is adapted to selectively lock the input sun gear of the second epicyclic gear train in a stationary position.
  • the transmission system comprises intermediate gearing connecting the mixing epicyclic gear train and the input sun gear of the second epicyclic gear train.
  • the second epicyclic gear train comprises a second sun gear engaged with a planet gear.
  • the sun gear is held stationary with respect to the transmission casing and the first braking element comprises clutch means for selectively connecting the output of the second epicyclic gear train to the system output shaft.
  • a method of operating a transmission system as claimed in any of the preceding claims comprises:
  • FIG. 1 is an illustration showing the general principle of the present invention.
  • FIG. 2 is a schematic diagram of an embodiment of transmission in accordance with the present invention.
  • an infinitely variable ratio transmission system comprises a transmission input shaft I and a transmission output shaft O.
  • a variator V preferably of the known toroidal race roller traction type, and a high regime clutch H.
  • the transmission input shaft I and the output of the variator V are also connected to a mixing epicyclic gear set E, the output of which is selectively connectable to the transmission output shaft O by means of a low regime clutch L.
  • the output of the epicyclic gear set E can also be locked to the transmission casing 40 by means of a further braking element in the form of clutch B.
  • One feature of the output of the mixing epicyclic gear set E is that at a certain variator ratio the output of the epicyclic gear set E is stationary (a condition which, when the transmission is in low regime, is known in the art as “geared neutral”).
  • the general principle of the present invention is that, with the high regime clutch H engaged and the low regime clutch L disengaged (i.e. with the transmission in high regime) the output of the epicyclic gear set E is continuously sensed and, when the output of the epicyclic gear set E is zero (or close to zero) the additional clutch B is engaged, which locks the output of the epicyclic gear set at zero rotation. Locking clutch B prevents the variator from moving away from the ratio which would result in geared neutral if the low-regime clutch were engaged.
  • FIG. 2 illustrates one embodiment of the present invention in more detail.
  • a continuously variable ratio transmission system comprises a variator V of the known toroidal race rolling traction type having two toroidally-recessed discs 10 arranged one at each end of the unit and a pair of similar output discs 12 , each facing a respective one of the input discs 10 and rotating with each other.
  • Sets of rollers 14 are mounted between the opposing faces of the input and output discs 10 , 12 to transmit drive from the input discs 10 to the output discs 12 with a ratio which is variable by tilting the rollers 14 .
  • the input discs 10 are connected to and driven by a system input shaft 16 .
  • the variator provides an output via a tubular variator output shaft 18 which is arranged coaxially with the input shaft 16 .
  • the end of the shaft 18 remote from the variator V drives the sun gear S 1 of a first, mixing epicyclic gear train E 1 .
  • the carrier C 1 of the gear train E 1 is connected to, and driven by, the input shaft 16 and is also connected to the inner of the two variator input discs 10 .
  • the carrier C 1 carries input planet gears P 1 which engage with, and are driven by, the sun gear S 1 .
  • the planet gears P 1 are each mounted on the carrier C 1 by means of an associated shaft 20 which additionally carries first and second output planet gears PX 1 and PY 1 .
  • Output planet gear PX 1 is identical to planet gear P 1 and transfers the summed output of the gear train E 1 via an output sun gear S 2 (of the same size as input sun gear S 1 ) to an intermediate output shaft 22 arranged coaxially with the system input shaft 16 .
  • Drive from the intermediate output shaft can be selectively transmitted via a high-regime clutch H to a system output shaft 24 .
  • Output planet gear PY 1 is of smaller diameter than planet gears P 1 and PX 1 and meshes with a pinion 26 formed on one end of a tubular intermediate output shaft 28 arranged coaxially with the input shaft 16 .
  • the opposite end of the intermediate output shaft is also provided with a pinion 30 of smaller diameter than pinion 26 .
  • the pinion 30 meshes with larger diameter planet gears P 2 of a second, simple reversing epicyclic gear set D 2 .
  • the planet gears P 2 are mounted on a carrier C 2 which is connected to a second tubular intermediate output shaft 32 arranged coaxially with the system input shaft 16 , and which in turn is connected to the system output shaft 24 .
  • the planet gears P 2 of the second epicyclic gear set E 2 are each located at one end of a respective shaft 34 mounted in the carrier C 2 .
  • the opposite end of each shaft 34 carries a further, smaller planet gear PX 2 which mesh with a sun gear 36 which is fixedly connected to the transmission casing 40 .
  • Drive from the second tubular intermediate output shaft 32 is taken continuously from the carrier C 2 and is selectively connected to the system output shaft 24 by means of a low-regime clutch L.
  • tubular intermediate output shaft 28 can be selectively braked to the transmission casing 40 by means of the additional clutch B referred to above.
  • the transmission can operate in one of three regimes, namely high regime, low regime and synchronous mode.
  • the high regime clutch H In high regime, the high regime clutch H is engaged and the low regime clutch L is disengaged.
  • An output from the other output planet gears PY 1 of the first mixing epicyclic gear set E 1 is also transmitted to the second epicyclic gear set E 2 .
  • the output is not transmitted to the carrier C 2 in high-regime since the low-regime clutch L is disengaged.
  • the tubular intermediate output shaft 28 i.e. the second output of the mixing epicyclic gearset E 1
  • the present invention takes advantage of this situation by detecting a geared neutral condition and applying the clutch B to lock the intermediate output shaft 28 to the transmission casing 40 in the condition in which the output of a second mixing epicyclic gear train formed by gears S 1 , P 1 , PY 1 and 26 and carrier C 1 is stationary.
  • the high regime clutch H In low regime, the high regime clutch H is disengaged and the low regime clutch L is engaged. Disengagement of the high regime clutch H isolates the system output shaft 24 from the output planet gear PX 1 of the mixing epicyclic gear set E 1 . Furthermore, engagement of the low regime clutch L allows the output drive from the first mixing epicyclic gear set E 1 to the second epicyclic gear set E 2 to be transferred to the carrier C 2 of the second epicyclic gear set E 2 by providing a reaction force from the transmission casing 40 . The drive is then transmitted to the second tubular intermediate output shaft 32 and thence to the system output shaft 24 .
  • Moving from high regime to low regime or vice versa can be achieved in so-called “synchronous mode” in which the transmission operates in a condition in which the intermediate output shaft 22 leading from the mixing epicyclic gear set E 1 and the second tubular intermediate output shaft 32 leading from the second epicyclic gear set E 2 rotate at (or very near) the same speed.
  • the clutch of the new regime is engaged, whereby both clutches are simultaneously engaged for a short time and the clutch of the old regime is then disengaged.
  • the only gears which are actively engaged in the mixing epicyclic gear set E 1 are the planetary gears P 1 and PY 1 , thereby minimising the losses which occur in the mixing epicyclic gear train E 1 , particularly in power recirculation mode.
  • the present invention allows the use of a mixing epicyclic gear set E 1 which does not have an annulus or ring gear. Not only does this reduce the weight of the transmission, but it also allows greater flexibility with the selection of the relative sizes of planetary gears P 1 , PX 1 and PY 1 . This in turn allows the speed of the components to be reduced and reduces the number of meshes to a minimum.

Abstract

A multiple-regime continuously variable ratio transmission system has a system input shaft (I), a system output shaft (O) and a continuously variable ratio transmission unit (variator) connected to the system input shaft and having a variator output shaft. A first mixing epicyclec gear train (P1) having inputs drivably connected to the variator output shaft (V) and the system input shaft via a first clutch (H) and a second mixing epicyclic gear train having inputs drivably connected to the variator output shaft and the system input shaft has an output (28) connected to a third epicyclic gear train (E2) having an output which is selectively connectable to the to the system output shaft via a first braking element (L). A second braking element (B) is adapted to lock the output (28) of the second mixing epicyclic gear train in a stationary position.

Description

  • The present invention relates to continuously variable ratio transmission systems.
  • It is known to provide a continuously variable ratio transmission system having system input and output shafts and a continuously variable ratio transmission unit (known as a variator) connected to the system input shaft and having a variator output shaft. A mixing epicyclic gear train receives drive from the system input and from the variator input. By appropriate use of clutches or other braking elements, the system can operate in a high-gearing regime or a low-gearing regime. Examples of such transmissions, which disclose arrangements having coaxial system input and output shafts, can be found in JP-A-6-174033 and JP-A-62-255655.
  • Inevitably, small power losses arise from the intermeshing of gears. In order to maximise efficiency, it is therefore desirable to reduce the number of gear meshes, particularly in the mixing epicyclic gear train where the power losses can be effectively be magnified during operation in a “power recirculation” mode.
  • Our co-pending United Kingdom patent application 0212186.1 addresses this problem by providing a mixing epicyclic gear train having an input sun gear drivably connected to the variator output shaft, a planet carrier drivably connected to the system input shaft and a first planet gear mounted on the planet carrier and drivingly engaged with the input sun gear. The first planet gear drives a first intermediate output shaft arranged coaxially with the system input shaft and is selectively connectable to the system output shaft via a first clutch. In addition, the first planet gear provides the input for a second epicyclic gear train having an output which is selectively connectable to the system output shaft via a braking element.
  • The variator is the lowest efficiency component of the transmission but it enables engine optimisation by ratio matching, resulting in improved overall economy. However, this is not possible at maximum power since this occurs only at one engine speed. If power loss is important, it may be beneficial to sacrifice variable ratio for best efficiency by removing the influence of the variator and operating it at a fixed ratio.
  • The overall result is to potentially avoid a slight reduction in the top speed of the vehicle to which the transmission is fitted.
  • In accordance with a first aspect of the present invention there is provided a multi-regime, continuously variable ratio transmission system, comprising:
  • a system input shaft and a system output shaft;
  • a continuously variable ratio transmission unit (variator) connected to the system input shaft and having a variator output shaft;
  • an output from the variator which is selectively connectable to the system output shaft via a first clutch;
  • a mixing epicyclic gear train having inputs drivably connected to the variator output shaft and the system input shaft and having an output which is selectively connectable to the system output shaft via a first braking element; and
  • a second braking element adapted to lock the output of the mixing epicyclic gear train in a stationary position.
  • Preferably the system input shaft, the system output shaft and the variator are arranged coaxially with each other and with a second epicyclic gear train comprising a second input sun gear driven by the output of the mixing epicyclic gear train and wherein the second braking element is adapted to selectively lock the input sun gear of the second epicyclic gear train in a stationary position.
  • Preferably the transmission system comprises intermediate gearing connecting the mixing epicyclic gear train and the input sun gear of the second epicyclic gear train.
  • Preferably the second epicyclic gear train comprises a second sun gear engaged with a planet gear.
  • Preferably the sun gear is held stationary with respect to the transmission casing and the first braking element comprises clutch means for selectively connecting the output of the second epicyclic gear train to the system output shaft.
  • In accordance with a second asepct of the present invention a method of operating a transmission system as claimed in any of the preceding claims, comprises:
  • detecting a condition in which the output from the variator is connected to the system output shaft via the first clutch and in which the mixing epicyclic gear train output is substantially stationary; and
  • applying the second braking element to lock the output of the mixing epicyclic gear train in the stationary position.
  • By way of example only, a specific embodiment of the present invention will now be described, with reference to the accompanying drawings, in which:
  • FIG. 1 is an illustration showing the general principle of the present invention; and
  • FIG. 2 is a schematic diagram of an embodiment of transmission in accordance with the present invention.
  • Referring firstly to FIG. 1, an infinitely variable ratio transmission system comprises a transmission input shaft I and a transmission output shaft O. Connected between the system input shaft I and the system output shaft O is a variator V, preferably of the known toroidal race roller traction type, and a high regime clutch H. The transmission input shaft I and the output of the variator V are also connected to a mixing epicyclic gear set E, the output of which is selectively connectable to the transmission output shaft O by means of a low regime clutch L.
  • However, it will also be observed that the output of the epicyclic gear set E can also be locked to the transmission casing 40 by means of a further braking element in the form of clutch B.
  • One feature of the output of the mixing epicyclic gear set E is that at a certain variator ratio the output of the epicyclic gear set E is stationary (a condition which, when the transmission is in low regime, is known in the art as “geared neutral”). The general principle of the present invention is that, with the high regime clutch H engaged and the low regime clutch L disengaged (i.e. with the transmission in high regime) the output of the epicyclic gear set E is continuously sensed and, when the output of the epicyclic gear set E is zero (or close to zero) the additional clutch B is engaged, which locks the output of the epicyclic gear set at zero rotation. Locking clutch B prevents the variator from moving away from the ratio which would result in geared neutral if the low-regime clutch were engaged.
  • The arrangement of FIG. 2 illustrates one embodiment of the present invention in more detail.
  • A continuously variable ratio transmission system comprises a variator V of the known toroidal race rolling traction type having two toroidally-recessed discs 10 arranged one at each end of the unit and a pair of similar output discs 12, each facing a respective one of the input discs 10 and rotating with each other. Sets of rollers 14 are mounted between the opposing faces of the input and output discs 10, 12 to transmit drive from the input discs 10 to the output discs 12 with a ratio which is variable by tilting the rollers 14.
  • The input discs 10 are connected to and driven by a system input shaft 16. The variator provides an output via a tubular variator output shaft 18 which is arranged coaxially with the input shaft 16. The end of the shaft 18 remote from the variator V drives the sun gear S1 of a first, mixing epicyclic gear train E1. The carrier C1 of the gear train E1 is connected to, and driven by, the input shaft 16 and is also connected to the inner of the two variator input discs 10. The carrier C1 carries input planet gears P1 which engage with, and are driven by, the sun gear S1. The planet gears P1 are each mounted on the carrier C1 by means of an associated shaft 20 which additionally carries first and second output planet gears PX1 and PY1. Output planet gear PX1 is identical to planet gear P1 and transfers the summed output of the gear train E1 via an output sun gear S2 (of the same size as input sun gear S1) to an intermediate output shaft 22 arranged coaxially with the system input shaft 16. Drive from the intermediate output shaft can be selectively transmitted via a high-regime clutch H to a system output shaft 24.
  • Output planet gear PY1 is of smaller diameter than planet gears P1 and PX1 and meshes with a pinion 26 formed on one end of a tubular intermediate output shaft 28 arranged coaxially with the input shaft 16. The opposite end of the intermediate output shaft is also provided with a pinion 30 of smaller diameter than pinion 26. The pinion 30 meshes with larger diameter planet gears P2 of a second, simple reversing epicyclic gear set D2. The planet gears P2 are mounted on a carrier C2 which is connected to a second tubular intermediate output shaft 32 arranged coaxially with the system input shaft 16, and which in turn is connected to the system output shaft 24.
  • The planet gears P2 of the second epicyclic gear set E2 are each located at one end of a respective shaft 34 mounted in the carrier C2. The opposite end of each shaft 34 carries a further, smaller planet gear PX2 which mesh with a sun gear 36 which is fixedly connected to the transmission casing 40. Drive from the second tubular intermediate output shaft 32 is taken continuously from the carrier C2 and is selectively connected to the system output shaft 24 by means of a low-regime clutch L.
  • In addition, it will be observed that the tubular intermediate output shaft 28 can be selectively braked to the transmission casing 40 by means of the additional clutch B referred to above.
  • The transmission can operate in one of three regimes, namely high regime, low regime and synchronous mode.
  • In high regime, the high regime clutch H is engaged and the low regime clutch L is disengaged. This allows the output of a first mixing epicyclic gear train formed by gears PX1 and S2 and carrier C1, which receives inputs from both the input discs 10 and the output discs 12 of the variator V, to be transmitted to the system output shaft 24 from output planet gears PX1 of the first epicyclic gear set E1, the output sun gear S2, the intermediate output shaft 22 and the high regime clutch H.
  • An output from the other output planet gears PY1 of the first mixing epicyclic gear set E1 is also transmitted to the second epicyclic gear set E2. The output is not transmitted to the carrier C2 in high-regime since the low-regime clutch L is disengaged.
  • However, as explained previously, for certain conditions of the transmission (known as “geared neutral”) the tubular intermediate output shaft 28 (i.e. the second output of the mixing epicyclic gearset E1) does not rotate. The present invention takes advantage of this situation by detecting a geared neutral condition and applying the clutch B to lock the intermediate output shaft 28 to the transmission casing 40 in the condition in which the output of a second mixing epicyclic gear train formed by gears S1, P1, PY1 and 26 and carrier C1 is stationary.
  • The effect of this is to effectively lock the variator in a fixed ratio corresponding to geared neutral. Power is then transmitted from input shaft 16 at fixed ratio via a first mixing epicyclic gear train formed by carrier C1 and the pairs of gears S2/PX1 and 26/PY1.
  • In low regime, the high regime clutch H is disengaged and the low regime clutch L is engaged. Disengagement of the high regime clutch H isolates the system output shaft 24 from the output planet gear PX1 of the mixing epicyclic gear set E1. Furthermore, engagement of the low regime clutch L allows the output drive from the first mixing epicyclic gear set E1 to the second epicyclic gear set E2 to be transferred to the carrier C2 of the second epicyclic gear set E2 by providing a reaction force from the transmission casing 40. The drive is then transmitted to the second tubular intermediate output shaft 32 and thence to the system output shaft 24.
  • Moving from high regime to low regime or vice versa can be achieved in so-called “synchronous mode” in which the transmission operates in a condition in which the intermediate output shaft 22 leading from the mixing epicyclic gear set E1 and the second tubular intermediate output shaft 32 leading from the second epicyclic gear set E2 rotate at (or very near) the same speed. In order to change regime, the clutch of the new regime is engaged, whereby both clutches are simultaneously engaged for a short time and the clutch of the old regime is then disengaged.
  • It will be observed that in low-regime, the only gears which are actively engaged in the mixing epicyclic gear set E1 are the planetary gears P1 and PY1, thereby minimising the losses which occur in the mixing epicyclic gear train E1, particularly in power recirculation mode. In high regime operation, there are no more meshes than prior art transmissions. However, it should also be noted that the present invention allows the use of a mixing epicyclic gear set E1 which does not have an annulus or ring gear. Not only does this reduce the weight of the transmission, but it also allows greater flexibility with the selection of the relative sizes of planetary gears P1, PX1 and PY1. This in turn allows the speed of the components to be reduced and reduces the number of meshes to a minimum.
  • The invention is not restricted to the details of the foregoing embodiment.

Claims (10)

1. A multi-regime, continuously variable ratio transmission system, comprising:
a system input shaft and a system output shaft;
a continuously variable ratio transmission unit (variator) connected to the system input shaft and having a variator output shaft;
an output from the variator which is selectively connectable to the system output shaft via a first clutch;
a mixing epicyclic gear train having inputs drivably connected to the variator output shaft and the system input shaft and having an output which is selectively connectable to the system output shaft via a first braking element; and
a second braking element adapted to lock the output of the mixing epicyclic gear train in a stationary position.
2. A transmission system as claimed in claim 1, wherein the system input shaft, the system output shaft and the variator are arranged coaxially with each other and with a second epicyclic gear train comprising a second input sun gear driven by an output of the mixing epicyclic gear train and wherein the second braking element is adapted to selectively lock the input sun gear of the second epicyclic gear train in a stationary position.
3. A transmission system as claimed in claim 2, comprising intermediate gearing connecting the mixing epicyclic gear train and the input sun gear of the second epicyclic gear train.
4. A transmission system as claimed in claim 2, wherein the second epicyclic gear train comprises a second sun gear engaged with a planet gear.
5. A transmission system as claimed in claim 4, wherein the second sun gear is held stationary with respect to the transmission casing and wherein the first braking element comprises clutch means for selectively connecting the output of the second epicyclic gear train to the system output shaft.
6. A method of operating a transmission system with
a system input shaft and a system output shaft;
a continuously variable ratio transmission unit (variator) connected to the system input shaft and having a variator output shaft;
an output from the variator which is selectively connectable to the system output shaft via a first clutch;
a mixing epicyclic gear train having inputs drivably connected to the variator output shaft and the system input shaft and having an output which is selectively connectable to the system output shaft via a first braking element; and
a second braking element adapted to lock the output of the mixing epicyclic gear train in a stationary position;
the method comprising:
detecting a condition in which the output from the variator is connected to the system output shaft via the first clutch and in which the mixing epicyclic gear train output is substantially stationary; and applying the second braking element to lock the output of the mixing epicyclic gear train in the stationary position.
7. (canceled)
8. (canceled)
9. A transmission system as claimed in claim 3, wherein the second epicyclic gear train comprises a second sun gear engaged with a planet gear.
10. A transmission system as claimed in claim 9, wherein the second sun gear is held stationary with respect to the transmission casing and wherein the first braking element comprises clutch means for selectively connecting the output of the second epicyclic gear train to the system output shaft.
US10/561,727 2003-07-01 2004-07-01 Continuously variable ratio transmission system Active 2025-05-05 US7530916B2 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
GBGB0315408.5A GB0315408D0 (en) 2003-07-01 2003-07-01 Continuously variable ratio transmission system
GB0315408.5 2003-07-01
PCT/GB2004/002841 WO2005003597A1 (en) 2003-07-01 2004-07-01 Continuously variable ratio transmission system

Publications (2)

Publication Number Publication Date
US20070042856A1 true US20070042856A1 (en) 2007-02-22
US7530916B2 US7530916B2 (en) 2009-05-12

Family

ID=27676463

Family Applications (1)

Application Number Title Priority Date Filing Date
US10/561,727 Active 2025-05-05 US7530916B2 (en) 2003-07-01 2004-07-01 Continuously variable ratio transmission system

Country Status (13)

Country Link
US (1) US7530916B2 (en)
EP (1) EP1639273B1 (en)
JP (1) JP2007516385A (en)
KR (1) KR20060034251A (en)
CN (1) CN100582528C (en)
AT (1) ATE410622T1 (en)
BR (1) BRPI0411997A (en)
CA (1) CA2529885A1 (en)
DE (1) DE602004016997D1 (en)
GB (1) GB0315408D0 (en)
MX (1) MXPA05014097A (en)
RU (1) RU2338938C2 (en)
WO (1) WO2005003597A1 (en)

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060142110A1 (en) * 2002-05-28 2006-06-29 Torotrak (Development) Limited Continuously variable ratio transmission system
WO2008142524A2 (en) * 2007-05-19 2008-11-27 Valtra Inc Vehicle transmission and transmission module
US20100240491A1 (en) * 2009-03-17 2010-09-23 Parag Vyas System for vehicle propulsion having and method of making same
US20100240492A1 (en) * 2009-03-17 2010-09-23 Parag Vyas System for vehicle propulsion having and method of making same
WO2014078583A1 (en) * 2012-11-17 2014-05-22 Dana Limited Continuously variable transmission
US8986150B2 (en) 2012-09-07 2015-03-24 Dana Limited Ball type continuously variable transmission/infinitely variable transmission
US9052000B2 (en) 2012-09-07 2015-06-09 Dana Limited Ball type CVT/IVT including planetary gear sets
US9194472B2 (en) 2013-03-14 2015-11-24 Dana Limited Ball type continuously variable transmission
US9347532B2 (en) 2012-01-19 2016-05-24 Dana Limited Tilting ball variator continuously variable transmission torque vectoring device
US9353842B2 (en) 2012-09-07 2016-05-31 Dana Limited Ball type CVT with powersplit paths
US9404414B2 (en) 2013-02-08 2016-08-02 Dana Limited Internal combustion engine coupled turbocharger with an infinitely variable transmission
US9541179B2 (en) 2012-02-15 2017-01-10 Dana Limited Transmission and driveline having a tilting ball variator continuously variable transmission
US9551404B2 (en) 2013-03-14 2017-01-24 Dana Limited Continuously variable transmission and an infinitely variable transmission variator drive
US9556943B2 (en) 2012-09-07 2017-01-31 Dana Limited IVT based on a ball-type CVP including powersplit paths
US9556941B2 (en) 2012-09-06 2017-01-31 Dana Limited Transmission having a continuously or infinitely variable variator drive
US9599204B2 (en) 2012-09-07 2017-03-21 Dana Limited Ball type CVT with output coupled powerpaths
US9638296B2 (en) 2012-09-07 2017-05-02 Dana Limited Ball type CVT including a direct drive mode
WO2017145178A1 (en) * 2016-02-23 2017-08-31 B R Girish Continuously variable transmission system using differential and brake
US9777815B2 (en) 2013-06-06 2017-10-03 Dana Limited 3-mode front wheel drive and rear wheel drive continuously variable planetary transmission
US10030594B2 (en) 2015-09-18 2018-07-24 Dana Limited Abuse mode torque limiting control method for a ball-type continuously variable transmission
US10030751B2 (en) 2013-11-18 2018-07-24 Dana Limited Infinite variable transmission with planetary gear set
US10088022B2 (en) 2013-11-18 2018-10-02 Dana Limited Torque peak detection and control mechanism for a CVP

Families Citing this family (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4720370B2 (en) * 2005-08-24 2011-07-13 株式会社エクォス・リサーチ Continuously variable transmission
GB0703351D0 (en) * 2007-02-21 2007-03-28 Torotrak Dev Ltd Continuously variable transmission
GB0717143D0 (en) * 2007-09-04 2007-10-17 Torotrak Dev Ltd Continuously variable transmission
CN102713361B (en) 2009-12-16 2015-11-25 艾里逊变速箱公司 Transducer blocking-valve system
CA2784348A1 (en) * 2009-12-16 2011-06-23 Allison Transmission, Inc. System and method for controlling endload force of a variator
CA2784373C (en) 2009-12-16 2017-11-07 Allison Transmission, Inc. Fast valve actuation system for an automatic transmission
US8578802B2 (en) 2009-12-16 2013-11-12 Allison Transmission, Inc. System and method for multiplexing gear engagement control and providing fault protection in a toroidal traction drive automatic transmission
US8676515B2 (en) 2009-12-16 2014-03-18 Allison Transmission, Inc. System and method for detecting clutch-related faults in an automatic transmission
CN102712312B (en) 2009-12-16 2015-08-05 艾里逊变速箱公司 Changer fault detection system
US8401752B2 (en) 2009-12-16 2013-03-19 Allison Transmission, Inc. Fail-to-neutral system and method for a toroidal traction drive automatic transmission
EP2606258B1 (en) 2010-08-16 2020-08-05 Allison Transmission, Inc. Gear scheme for infinitely variable transmission
EP2652366B1 (en) 2010-12-15 2017-11-29 Allison Transmission, Inc. Variator multiplex valve scheme for a torroidal traction drive transmission
WO2012082843A1 (en) 2010-12-15 2012-06-21 Long Charles F Dual pump regulator system for a motor vehicle transmission
KR20130141635A (en) 2010-12-15 2013-12-26 알리손 트랜스미션, 인크. Variator switching valve scheme for a torroidal traction drive transmission
CA2830929A1 (en) 2011-04-04 2012-10-11 Fallbrook Intellectual Property Company Llc Auxiliary power unit having a continuously variable transmission
CA2850224A1 (en) 2011-10-03 2013-04-11 Fallbrook Intellectual Property Company Llc Refrigeration system having a continuously variable transmission
US8579753B2 (en) * 2012-02-10 2013-11-12 GM Global Technology Operations LLC Compound planetary front wheel drive continuously variable transmission

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6155951A (en) * 1997-01-31 2000-12-05 Zf Friedrichshafen Ag Toroidal drive
US20020169048A1 (en) * 2001-04-28 2002-11-14 Steffen Henzler Speed change transmission arrangement including a continuously variable toriodal transmission
US20060142110A1 (en) * 2002-05-28 2006-06-29 Torotrak (Development) Limited Continuously variable ratio transmission system

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3702597B2 (en) * 1997-08-12 2005-10-05 日本精工株式会社 Toroidal type continuously variable transmission
JP3697860B2 (en) * 1997-10-07 2005-09-21 日本精工株式会社 Toroidal type continuously variable transmission
JP4062809B2 (en) 1999-02-03 2008-03-19 日本精工株式会社 Continuously variable transmission

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6155951A (en) * 1997-01-31 2000-12-05 Zf Friedrichshafen Ag Toroidal drive
US20020169048A1 (en) * 2001-04-28 2002-11-14 Steffen Henzler Speed change transmission arrangement including a continuously variable toriodal transmission
US20060142110A1 (en) * 2002-05-28 2006-06-29 Torotrak (Development) Limited Continuously variable ratio transmission system

Cited By (34)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7407459B2 (en) * 2002-05-28 2008-08-05 Torotrak (Development) Limited Continuously variable ratio transmission system
US20060142110A1 (en) * 2002-05-28 2006-06-29 Torotrak (Development) Limited Continuously variable ratio transmission system
WO2008142524A2 (en) * 2007-05-19 2008-11-27 Valtra Inc Vehicle transmission and transmission module
WO2008142524A3 (en) * 2007-05-19 2009-03-19 Valtra Inc Vehicle transmission and transmission module
US20100240491A1 (en) * 2009-03-17 2010-09-23 Parag Vyas System for vehicle propulsion having and method of making same
US20100240492A1 (en) * 2009-03-17 2010-09-23 Parag Vyas System for vehicle propulsion having and method of making same
US8535200B2 (en) 2009-03-17 2013-09-17 General Electric Company Vehicle propulsion system having a continuously variable transmission and method of making same
US9347532B2 (en) 2012-01-19 2016-05-24 Dana Limited Tilting ball variator continuously variable transmission torque vectoring device
US9541179B2 (en) 2012-02-15 2017-01-10 Dana Limited Transmission and driveline having a tilting ball variator continuously variable transmission
US9556941B2 (en) 2012-09-06 2017-01-31 Dana Limited Transmission having a continuously or infinitely variable variator drive
US9689477B2 (en) 2012-09-07 2017-06-27 Dana Limited Ball type continuously variable transmission/infinitely variable transmission
US9556943B2 (en) 2012-09-07 2017-01-31 Dana Limited IVT based on a ball-type CVP including powersplit paths
US9353842B2 (en) 2012-09-07 2016-05-31 Dana Limited Ball type CVT with powersplit paths
US10006527B2 (en) 2012-09-07 2018-06-26 Dana Limited Ball type continuously variable transmission/infinitely variable transmission
US9416858B2 (en) 2012-09-07 2016-08-16 Dana Limited Ball type continuously variable transmission/infinitely variable transmission
US9052000B2 (en) 2012-09-07 2015-06-09 Dana Limited Ball type CVT/IVT including planetary gear sets
US10088026B2 (en) 2012-09-07 2018-10-02 Dana Limited Ball type CVT with output coupled powerpaths
US9638296B2 (en) 2012-09-07 2017-05-02 Dana Limited Ball type CVT including a direct drive mode
US8986150B2 (en) 2012-09-07 2015-03-24 Dana Limited Ball type continuously variable transmission/infinitely variable transmission
US9599204B2 (en) 2012-09-07 2017-03-21 Dana Limited Ball type CVT with output coupled powerpaths
US10030748B2 (en) 2012-11-17 2018-07-24 Dana Limited Continuously variable transmission
WO2014078583A1 (en) * 2012-11-17 2014-05-22 Dana Limited Continuously variable transmission
US9644530B2 (en) 2013-02-08 2017-05-09 Dana Limited Internal combustion engine coupled turbocharger with an infinitely variable transmission
US9404414B2 (en) 2013-02-08 2016-08-02 Dana Limited Internal combustion engine coupled turbocharger with an infinitely variable transmission
US9551404B2 (en) 2013-03-14 2017-01-24 Dana Limited Continuously variable transmission and an infinitely variable transmission variator drive
US9933054B2 (en) 2013-03-14 2018-04-03 Dana Limited Continuously variable transmission and an infinitely variable transmission variator drive
US9689482B2 (en) 2013-03-14 2017-06-27 Dana Limited Ball type continuously variable transmission
US9638301B2 (en) 2013-03-14 2017-05-02 Dana Limited Ball type continuously variable transmission
US9194472B2 (en) 2013-03-14 2015-11-24 Dana Limited Ball type continuously variable transmission
US9777815B2 (en) 2013-06-06 2017-10-03 Dana Limited 3-mode front wheel drive and rear wheel drive continuously variable planetary transmission
US10030751B2 (en) 2013-11-18 2018-07-24 Dana Limited Infinite variable transmission with planetary gear set
US10088022B2 (en) 2013-11-18 2018-10-02 Dana Limited Torque peak detection and control mechanism for a CVP
US10030594B2 (en) 2015-09-18 2018-07-24 Dana Limited Abuse mode torque limiting control method for a ball-type continuously variable transmission
WO2017145178A1 (en) * 2016-02-23 2017-08-31 B R Girish Continuously variable transmission system using differential and brake

Also Published As

Publication number Publication date
CA2529885A1 (en) 2005-01-13
EP1639273B1 (en) 2008-10-08
JP2007516385A (en) 2007-06-21
WO2005003597A1 (en) 2005-01-13
ATE410622T1 (en) 2008-10-15
US7530916B2 (en) 2009-05-12
BRPI0411997A (en) 2006-09-05
RU2006101863A (en) 2006-06-10
MXPA05014097A (en) 2006-03-17
KR20060034251A (en) 2006-04-21
DE602004016997D1 (en) 2008-11-20
CN1820155A (en) 2006-08-16
RU2338938C2 (en) 2008-11-20
GB0315408D0 (en) 2003-08-06
EP1639273A1 (en) 2006-03-29
CN100582528C (en) 2010-01-20

Similar Documents

Publication Publication Date Title
US7530916B2 (en) Continuously variable ratio transmission system
US7407459B2 (en) Continuously variable ratio transmission system
EP2971864B1 (en) Split power infinitely variable transmission architecture
US9261181B2 (en) Continuously variable power-split vehicle transmission
US5823051A (en) Multi-speed power transmission
US9188200B2 (en) Multi-speed transmission
US4976670A (en) Power transmission
US20050176547A1 (en) Continuously variable transmission system
WO2006032870A1 (en) Continuously variable ratio transmission system
JP2005527754A5 (en)
GB2384531A (en) Multi-regime CVT with coaxial input and output shafts
US6561942B2 (en) Dual mode variable ratio transmission
GB2410302A (en) Multi-regime CVT with coaxial input and output shafts
GB2397630A (en) A multi-regime CVT system with coaxial input and output shafts
GB2336634A (en) Four-speed planetary gearing with ratio shift by operation of a single friction device
JPH074478A (en) Speed change gears with 3 sets of part gearing
EP1369624A1 (en) Continuosusly variable ratio transmission system
JPH09196129A (en) Continuously variable transmission
AU2003202087A1 (en) Continuously variable transmission system

Legal Events

Date Code Title Description
AS Assignment

Owner name: TOROTRAK (DEVELOPMENT) LIMITED, GREAT BRITAIN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:GREENWOOD, CHRISTOPHER JOHN;REEL/FRAME:018060/0061

Effective date: 20060630

STCF Information on status: patent grant

Free format text: PATENTED CASE

CC Certificate of correction
FPAY Fee payment

Year of fee payment: 4

FEPP Fee payment procedure

Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

REMI Maintenance fee reminder mailed
FPAY Fee payment

Year of fee payment: 8

SULP Surcharge for late payment

Year of fee payment: 7

AS Assignment

Owner name: ALLISON TRANSMISSION, INC., INDIANA

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:TOROTRAK (DEVELOPMENT) LIMITED;REEL/FRAME:046112/0801

Effective date: 20180327

AS Assignment

Owner name: ALLISON TRANSMISSION, INC., INDIANA

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:TOROTRAK (DEVELOPMENT) LIMITED;REEL/FRAME:046299/0787

Effective date: 20180327

MAFP Maintenance fee payment

Free format text: PAYMENT OF MAINTENANCE FEE, 12TH YEAR, LARGE ENTITY (ORIGINAL EVENT CODE: M1553); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

Year of fee payment: 12